Polyinosinic acid-polycytidylic acid-based adjuvant

ABSTRACT

The present invention provides a polynucleotide adjuvant composition and methods of use in eliciting an immune response. The present invention also provides an immunogenic composition comprising the polynucleotide adjuvant composition together with an antigen (e.g., as in a vaccine). The adjuvant compositions of the invention have particular physical properties (e.g., molecular weight, concentration, and pH) which address the need for a safe adjuvant for eliciting an enhanced immune response. The present invention further contemplates methods of use of such adjuvant compositions, particularly in eliciting an immune response to an antigenic compound.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/551,847filed Jun. 23, 2006, which application claims priority to applicationserial no. CN2005/000810, filed Jun. 8, 2005, the disclosures of whichapplications are incorporated in their entirety herein.

FIELD OF INVENTION

The invention generally relates to adjuvant compositions and methods oftheir use in enhancing an immune response, more particularly tocompounds, vaccines and methods for enhancing the immunogenicity of anantigen, and more particularly to polynucleotide adjuvant compositions,vaccines comprising the polynucleotide adjuvant compositions, andmethods of using said polynucleotide adjuvant compositions and vaccinesto enhance immune responses in a host.

BACKGROUND OF INVENTION Description of Related Art

The immune system may exhibit both specific and nonspecific immunity.Generally, B and T lymphocytes, which display specific receptors ontheir cell surface for a given antigen, produce specific immunity. Theimmune system may respond to different antigens in two ways:

1) humoral-mediated immunity, which includes B cell stimulation andproduction of antibodies or immunoglobulins, antigen-presenting cells(APCs), and helper T cells (Th1 and Th2), and 2) cell-mediated immunity(CMI), which generally involves T cells including cytotoxic Tlymphocytes (CTLs), although other cells are also involved in thegeneration of a CTL response (e.g., Th1 and/or Th2 cells and APCs).

Nonspecific immunity encompasses various cells and mechanisms such asphagocytosis (the engulfing of foreign particles or antigens) bymacrophages or granulocytes, and natural killer (NK) cell activity,among others. Nonspecific immunity relies on mechanisms lessevolutionarily advanced and does not display the acquired nature ofspecificity and memory, which are exemplary hallmarks of a specificimmune response. The key differences between specific and nonspecificimmunity are based upon B and T cell specificity. These cellspredominantly acquire their responsiveness after activation with aspecific antigen and have mechanisms to display memory in the event offuture exposure to that specific antigen. As a result, vaccination(involving specificity and memory) is an effective protocol to protectagainst harmful pathogens.

Adjuvants are generally compounds, that when administered with anantigen (either mixed with, or given prior to the administration of theantigen) enhances or modifies the immune response to that particularantigen.

Exemplary adjuvants that have been used to enhance an immune responseinclude aluminum compounds (all generally referred to as “Alum”),oil-in-water emulsions (complete Freund's adjuvant (CFA) is anoil-in-water emulsion containing dried, heat-killed Mycobacteriumtuberculosis organisms), Saponin (isolated from the bark of QuillajaSaponoria, the adjuvant active component known as Quile A), CpG ODN(synthetic oligodeoxynucleotide containing unmethylated CpGdinucleotides), MPL (derived from the lipopolysaccharide of Salmonellaminnesota Re595), Liposomes (usually made up of biodegradable materialssuch as phospholipids) and Biodegradable polymer microspheres (made froma variety of polymers such as PLGA, polyphosphazene and polyanhydrides).The adjuvant properties of these compounds have been evaluated with eachadjuvant showing advantages and disadvantages.

The biggest issue with the use of adjuvants for human vaccines,particularly routine childhood vaccines, is the toxicity and adverseside-effects of most of the adjuvant formulations. The application ofnew technologies to vaccine development is leading to purified, subunitand synthetic antigens, which tend to have poor immunogenicity. Thedevelopment of new adjuvants, to improve immunogenicity/efficacy andreduce side effects, presents one of the major challenges of vaccineresearch and development.

Polynucleotide complexes have been investigated for their variousapplications including acting as adjuvants. Double-stranded RNAs(dsRNAs) are very potent biologic modifiers that can exert a profoundinfluence on cells at nanomolar concentrations. The modulating effectsof dsRNA include a broad spectrum of actions at the molecular andcellular levels.

At the molecular level, dsRNAs can elicit; biological effects such asinterferon synthesis, induction of protein kinase, enhancement ofhistocompatibility antigen and inhibition of metabolism. And at thecellular level, dsRNA can elicit biological effects such aspyrogenicity, mitogenicity, macrophage activation, activation ofcell-mediated immunity and induction of antiviral state. One promisingpotential of dsRNAs is its immunomodulating effect in antimicrobialtherapies. U.S. Pat. No. 4,124,702 disclosed that double strandedpolynucleotides induced interferon induction in living animal cells.U.S. Pat. No. 3,906,092 disclosed that the antibody response to anadjuvant type vaccine was augmented by incorporation in the vaccine of apolynucleotide or a complex of polynucleotides. Houston et al.established PICLC (polyinosinic acid polycytidylic acidpoly-L-lysinecarboxy-moethylcellulose complex) as a potent adjuvant byincreasing primary antibody response without the aid of an additionaladjuvant. Houston et al., Infection and Immunity, 14: 318-9, 1976C.Mycoviral dsRNA was found to enhance significantly the hemagglutinatingantibody response to sheep red blood cells (sRBC). Wright andAdler-Moore, Biochemical and Biophysical Research Communications, 131:949-45, 1985.

However, PIC (polyinosinic acid polycytidylic acid) manifests severetoxicity when used in animals. For example, Phillips et al. reportedthat severe toxic manifestations were elicited in dogs upon thesub-chronic administration of PIC at a dose of 2.0 mg/kg. Toxicity wascharacterized by decreased spontaneous activity, poor co-ordination,vomiting, anorexia, weight loss, hematologic changes reflectingdecreased hematopoiesis, increased alkaline phosphatase and transaminaseactivities, thymus degeneration, destruction of bone marrow, dilatationof hepatic sinusoidal capillaries in the centrolobular areas, necrosisof liver cells, collapse of hepatic structures, and a generalizedarthritis. See, Phillips et al., Toxicology and Applied Pharmacology,18: 220-30, 1971.

PIC, one of most studied polynucleotide complexes, was not effectivewhen used in monkeys and humans due to its instability in the body afteradministration. Thus, PIC has been modified in many ways to overcome oneor another deficiency. For example, a complex ofpolyriboinosinic-polyribocytidylic acid with poly-L-lysine hydrobromideis about 5 to 15 times as resistant to hydrolysis by pancreaticribonuclease as the parent PIC. Another example is the dsRNA polyICLC,or PICLC for short, that was found highly effective as an antiviral orantitumor agent. PICLC is a synthetic dsRNA composed of polyriboinosinicand polyribocytidylic acid strands (PIC). Although PICLC is a promisingimmunomodulator which has great potential in antimicrobial andanticancer therapies, it has been shown to produce serious side effectsin humans, especially when the drug is administered in multiple highdoses. Some of the reported side effects include fever, hypotension,leukopenia, myalgia, thrombocytopenia and polyarthalgia. The inherenttoxicity problem must be overcome to render PICLC safe for use inhumans. Furthermore, the therapeutic efficacy of poly ICLC is limited byits stability in vivo.

An antiviral drug composed of polyinosinic acid-polycytidylic acid (PolyI:C), kanamycin and calcium (Av-PICKCa) is used for treating viralinfections. Av-PICKCa has been shown to be able to induce interferon andinterleukin-2 production. Av-PICKCa administered alone as an antiviraldrug stimulates a non-specific immune response, i.e., stimulates a formof interferon that is not specific to any particular antigen. Thisanti-viral response is profoundly different from the antigen-specificimmune response generated when an adjuvant is administered inconjunction with an antigen.

More importantly, the inventor of the present invention discovered thatAv-PICKCa had the properties of an adjuvant, i.e., the ability to elicita specific immune response when administered with an antigen. Further,the inventor further discovered that Av-PICKCa was an effective adjuvantwhen used together with rabies and hemorrhagic fever antigens.

Lin et al. described that Av-PICKCa can be used as an adjuvant (Lin, etal., A new immunostimulatory complex (PICKCa) in experimental rabies:antiviral and adjuvant effects, Arch Virol, 131: 307-19, 1993; andChinese Patent No. 93105862.7). The Chinese Patent No. 93105862.7provides for the use of the general composition of Poly I:C, kanamycinand calcium (PICKCa) as an adjuvant in a vaccine for human and mammalianapplication.

Samples of Av-PICKCa are heterogeneous with respect to size and weightof the molecules. Av-PICKCa is described in the literature in terms ofan average or range of sedimentation co-efficient values as measured bySvedbergs S. The antiviral drug Av-PICKCa exists in one embodiment from5 S to 8 S (Source A) see, Zhung J. C., Research recollection ofpolyinosinic-polycytidylic acid (PIC). The paper of fifth Chineseinterferon conference in clinical application and theory, Siam 1985, pp23-28. In other embodiments Av-PICKCa exists with a sedimentationco-efficient of 4 S to 12 S with an average of 6 S (Source B) or 5 S to12 S with an average of 7 S (Source C) or 8 S to 10 S (Source D) see HuQ. G., Tianjin Av-PICKCa's laboratory research and clinical application,Fujian Medical Journal, 1983.12; (6): 28-30 and Hu Q. G. Chinese Medicaland Pharmaceutical Industry Journal, 1983 (9) 3134.

The sedimentation co-efficient of this heterogeneous collection ofmolecules in Av-PICKCa is convertible to an equivalent molecular weight(mw in Daltons) using the conversion formula mw=1,100×S^(2.2) (see Su B.X. et al; Introduction of Biochemical Technology, 1^(st) Edition,Zhongshan University, 1978, 356-357). The results of the conversion intoDaltons are presented in the table below:

TABLE A Characteristics of Av-PICKCa Sedimentation Molecular Av-PICKCaCo-efficient S Weight Daltons Source Min. Max. Avg. Min. Max. Avg. A 58 * 38,000 107,000 * B 4 12 6 23,000 260,000 57,000 C 5 12 7 38,000260,000 79,000 D 8 10 * 107,000 174,000 * * data not cited in reference

The original research on Av-PICKCa as an adjuvant by Lin et al. was witha sample having molecules that had similar characteristics to Source A,i.e., a sedimentation co-efficient of 5 S to 8 S, that is an equivalentmolecular weight of molecules ranging from 38,000 Daltons to 107,000Daltons. (see Lin et al., supra).

All forms of PICKCa were believed to be equally safe and effective giventhat Av-PICKCa is essentially a form of PICKCa and further given thehistorical use of Av-PICKCa as an antiviral drug. However, this provednot to be the case. Research conducted by the inventor demonstrates thatthe efficacy and toxicity of PICKCa, when used as an adjuvant incombination with an antigen, actually vary with different molecularweights. The inventor found that Av-PICKCa does not provide the optimalefficacy/safety profile for use as an adjuvant and that PICKCa doesinduce unacceptable adverse side effects under certain conditions. Thusthere remains a need for an adjuvant which is more suitable for humanuse and which is safe and effective in providing the desired immunogeniceffect. The current invention addresses this need and provides otheradvantages that will be apparent with reference to the detaileddescription.

Literature

The following references may be of interest:

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SUMMARY OF THE INVENTION

The present invention provides a polynucleotide adjuvant composition andmethods of use in eliciting an immune response. The present inventionalso provides an immunogenic composition comprising the polynucleotideadjuvant composition together with an antigen (e.g., as in a vaccine).The adjuvant compositions of the invention have particular physicalproperties (e.g., molecular weight, size, concentration and pH) whichaddress the need for an effective and safe adjuvant for eliciting anenhanced immune response. The present invention further contemplatesmethods of use of such adjuvant compositions, particularly in elicitingan immune response to an antigenic compound.

In one embodiment, the invention provides a polynucleotide adjuvantcomposition comprising polyriboinosinic-polyribocytidylic acid (PIC), anantibiotic and a positive ion, wherein the antibiotic may be kanamycinand the positive ion may be a divalent ion such as calcium. The presentinvention also provides an immunogenic composition comprising thepolynucleotide adjuvant composition together with an antigen or vaccine.

The present invention serves to advance the body of knowledge bydefining a novel composition that may be used safely and effectively asan adjuvant to enhance and/or modify the immune response in an animal orhuman host. While prior disclosures demonstrate the application of theantiviral drug Av-PICKCa for use as an adjuvant, this form of PICKCa wasobserved to elicit only a limited specific immune response whenadministered with an antigen. Further PICKCa was found to elicitunacceptable adverse side effects under certain conditions.

The present invention addresses these problems by providing an adjuvantcomposition, referred to generally herein as “PIKA”, which may beadministered most effectively and safely as an adjuvant in animals,including humans.

PIKA is a composition comprising a polynucleotide, an antibiotic and apositive ion that has been specifically developed as an adjuvant.Included in the invention are compositions having the unique productattributes that make it most suitable for use as an adjuvant in animmunogenic composition to be administered to animals and/or humans.

More specifically, the present invention provides a polynucleotideadjuvant composition comprising a polynucleotide, an antibiotic and apositive ion, wherein the polynucleotide may bepolyriboinosinic-polyribocytidylic acid (PIC); the antibiotic iskanamycin, an anthracycline, butirosin sulfate, a gentamicin,hygromycin, amikacin, dibekacin, nebramycin, metrzamide, neomycin,puromycin, streptomycin or streptozocin; and the ion is calcium,cadmium, lithium, magnesium, cerium, cesium, chromium, cobalt,deuterium, gallium, iodine, iron, or zinc.

More specifically, the present invention provides the specification,including the molecular weight, concentration and pH, of the compositioncomprising a polynucleotide, an antibiotic and a positive ion thataddresses the need for a safe adjuvant which elicits the maximum desiredimmune response.

The present invention also provides an immunogenic compositioncomprising the polynucleotide adjuvant composition and an antigen orvaccine.

In certain embodiments the present invention is in the form of a kitcomprising the polynucleotide adjuvant and an immunogenic compound.

Furthermore, the present invention provides a method for enhancingimmune responses to an antigenic compound by administering to a host theimmunogenic composition. The host can be a human being or animal. Theadministration can be done by injection, such as intramuscular,intraperitoneal, intravenous or subcutaneous injection, or byinhalation. In other embodiments, the immunogenic composition can bedelivered rectally, vaginally, nasally, orally, opthamalically,topically, transdermally, or intradermally.

Accordingly, the present invention provides an adjuvant and animmunogenic composition that can be used safely in humans and animals.

Accordingly, in one aspect the invention features a polynucleotideadjuvant composition comprising a polyriboinosinic-polyribocytidylicacid (PIC), an antibiotic, and a positive ion, wherein the compositioncontains molecules of the adjuvant heterogeneous for molecular weighthaving a molecular weight of from about 66,000 to 1,200,000 Daltons.

In related embodiments, the polynucleotide adjuvant compositionmolecules in the composition are heterogeneous for molecular weight,where the molecular weight is from about 300,000 to 1,200,000 Daltons,or from about 66,000 to 660,000 Daltons, or from about 300,000 to660,000 Daltons, or from about 300,000 to 2,000,000 Daltons, or fromabout 300,000 to 4,000,000 Daltons, or from about 500,000 to 1,000,000Daltons, or from about 1,000,000 to 1,500,000 Daltons, or from about1,500,000 to 2,000,000 Daltons, or from about 2,000,000 to 2,500,000Daltons, or from about 2,500,000 to 3,000,000 Daltons, or from about3,000,000 to 3,500,000 Daltons, or from about 3,500,000 to 4,000,000Daltons, or from about 4,000,000 to 4,500,000 Daltons, or from about4,500,000 to 5,000,000 Daltons.

In related embodiments, the polynucleotide adjuvant compositionmolecules in the composition have an average molecular weight equal toor greater than 150,000 Daltons, or equal to or greater than 250,000Daltons, or equal to or greater than 350,000 Daltons, or equal to orgreater than 500,000 Daltons, or equal to or greater than 650,000Daltons, or equal to or greater than 750,000 Daltons, or equal to orgreater than 1,000,000 Daltons, or equal to or greater than 1,200,000Daltons, or equal to or greater than 1,500,000 Daltons, or equal to orgreater than 2,000,000 Daltons.

Accordingly, in one aspect the invention features, a polynucleotideadjuvant composition comprising a polyriboinosinic-polyribocytidylicacid (PIC), an antibiotic, and a positive ion wherein the compositioncontains molecules of the adjuvant heterogeneous for molecular sizehaving a sediment co-efficient Svedbergs (S) of from about 6.43 S to24.03 S.

In related embodiments, the polynucleotide adjuvant compositionmolecules in the composition are heterogeneous for molecular size, wherethe molecular size is from about 12.8 S to 24.03 S, or from about 6.43to 18.31 S, or from about 12.8 to 18.31 S, or from about 12.8 S to 30.31S, or from about 12.8 S to 41.54 S, or from about 13.5 S, to 18.31 S, orfrom about 13.5 S to 24.03 S, or from about 16.14 to 22.12 S, or fromabout 22.12 S to 26.6 S, or from about 26.6 S to 30.31 S, or from about30.31 S to 33.55 S, or from about 33.55 S to 36.45 S, or from about36.45 S to 39.1 S, or from about 39.1 S to 41.54 S, or from about 41.54S to 43.83 S, or from about 43.83 S to 45.95 S.

In further related embodiments, the polynucleotide adjuvant compositionhas an average sedimentation co-efficient (Svedbergs) greater than 9, orgreater than 12, or greater than 13.5, or greater than 15, or greaterthan 16, or greater than 17, or greater than 18, or greater than 19, orgreater than 20, or greater than 21, or greater than 22 or greater than25, or greater than 30.

In a related embodiment the antibiotic in the composition is kanamycin,neomycin, an anthracycline, butirosin sulfate, a gentamicin, hygromycin,amikacin, dibekacin, nebramycin, metrzamide, puromycin, streptomycin orstreptozocin.

In a further related embodiment, the adjuvant composition furthercomprises a source of calcium ions.

In another related embodiment, the positive ion in the composition iscalcium, cadmium, lithium, magnesium, cerium, cesium, chromium, cobalt,deuterium, gallium, iodine, iron, or zinc. The positive can be in theform of inorganic salts or organic complexes.

The source of calcium ions can be provided by, for example, calciumchloride, calcium carbonate, calcium fluoride, calcium hydroxide,calcium phosphates, or calcium sulfate.

In one aspect of particular interest, the invention provides apolynucleotide adjuvant composition comprisingpolyriboinosinic-polyribocytidylic acid (PIC), kanamycin and calcium,wherein the composition includes molecules of the adjuvant heterogeneousfor molecular weight having a molecular weight of from about 66,000 to1,200,000 Daltons.

In related embodiments, the polyriboinosinic-polyribocytidylic acid(PIC), kanamycin and calcium molecules have a molecular weight fromabout 300,000 to 1,200,000 Daltons, or from about 66,000 to 660,000Daltons, or from about 300,000 to 660,000 Daltons, or from about 300,000to 2,000,000 Daltons, or from about 300,000 to 4,000,000 Daltons, orfrom about 500,000 to 1,000,000 Daltons, or from about 1,000,000 to1,500,000 Daltons, or from about 1,500,000 to 2,000,000 Daltons, or fromabout 2,000,000 to 2,500,000 Daltons, or from about 2,500,000 to3,000,000 Daltons, or from about 3,000,000 to 3,500,000 Daltons, or fromabout 3,500,000 to 4,000,000 Daltons, or from about 4,000,000 to4,500,000 Daltons, or from about 4,500,000 to 5,000,000 Daltons.

In other related embodiments, the polyriboinosinic-polyribocytidylicacid (PIC), kanamycin and calcium molecules of the adjuvantheterogeneous for molecular weight having an average molecular weightequal to or greater than 150,000 Daltons, equal to or greater than250,000 Daltons, or equal to or greater than 350,000 Daltons, or equalto or greater than 500,000 Daltons, or equal to or greater than 650,000Daltons, or equal to or greater than 750,000 Daltons, or equal to orgreater than 1,000,000 Daltons, or equal to or greater than 1,200,000Daltons, or equal to or greater than 1,500,000 Daltons, or equal to orgreater than 1,500,000 Daltons.

In one aspect of particular interest, the invention provides apolynucleotide adjuvant composition comprisingpolyriboinosinic-polyribocytidylic acid (PIC), kanamycin and calciumwherein the composition includes molecules of the adjuvant heterogeneousfor molecular size having a sediment co-efficient Svedbergs (S) of fromabout 6.43 S to 24.03 S.

In related embodiments, the polynucleotide adjuvant compositionmolecules in the composition are heterogeneous for molecular size, wherethe molecular size is from about 12.8 S to 24.03 S, or from about 6.43to 18.31 S, or from about 12.8 to 18.31 S, or from about 12.8 S to 30.31S, or from about 12.8 S to 41.54 S, or from about 13.5 S to 18.31 S, orfrom about 13.5 S to 24.03 S, or from about 16.14 to 22.12 S, or fromabout 22.12 S to 26.6 S, or from about 26.6 S to 30.31 S, or from about30.31 S to 33.55 S, or from about 33.55 S to 36.45 S, or from about36.45 S to 39.1 S, or from about 39.1 S to 41.54 S, or from about 41.54S to 43.83 S, or from about 43.83 S to 45.95 S.

In still other related embodiments, thepolyriboinosinic-polyribocytidylic acid (PIC), kanamycin and calcium hasan average sedimentation co-efficient greater than 9, or greater than12, or greater than 13.5, or greater than 15, or greater than 16, orgreater than 17, or greater than 18, or greater than 19, or greater than20, or greater than 21, or greater than 22, or greater than 25, orgreater than 30.

In some embodiments the invention provides a polynucleotide adjuvantcomposition comprising polyriboinosinic-polyribocytidylic acid (PIC),kanamycin and calcium, wherein it may be preferable for the compositionto exclude molecules, particularly to an extent that such excludedmolecules have no significant immunogenic effect, wherein the excludedmolecules have a molecular weight about or below 30,000 Daltons, aboutor below 40,000 Daltons, about or below 50,000 Daltons, about or below60,000 Daltons, about or below 70,000 Daltons, about or below 80,000Daltons, about or below 90,000 Daltons, about or below 100,000 Daltons,about or below 150,000 Daltons, about or below 200,000 Daltons, about orbelow 250,000 Daltons, about or below 300,000 Daltons, about or below350,000 Daltons, about or below 400,000 Daltons, about or below 450,000Daltons, about or below 500,000 Daltons, about or below 600,000 Daltons,about or below 700,000 Daltons, about or below 800,000 Daltons, about orbelow 900,000 Daltons, about or below 1,000,000 Daltons.

In some embodiments the invention provides a polynucleotide adjuvantcomposition comprising polyriboinosinic-polyribocytidylic acid (PIC),kanamycin and calcium wherein it may be preferable for the compositionto exclude molecules, particularly to an extent that such excludedmolecules have no significant immunogenic effect, wherein the excludedmolecules have a molecular size about or below 4.49 S, about or below5.12 S, about or below 5.67 S, about or below 6.16 S, about or below 6.6S, about or below 7.02 S, about or below 7.4 S, about or below 7.77 S,about or below 9.34 S, about or below 10.64 S, about or below 11.78 S,about or below 12.8 S, about or below 13.73 S, about or below 14.59 S,about or below 15.39 S, about or below 16.14 S, about or below 17.54 S,about or below 18.81 S, about or below 19.99 S, about or below 21.09 S,about or below 22.12 S.

In one aspect of particular interest, the invention provides for animmunogenic composition for enhancing the antigenicity of an antigeniccompound comprising the polynucleotide adjuvant composition.

In related embodiments, the immunogenic composition comprises thepolynucleotide adjuvant and an antigen.

In related embodiments, the source of the antigen is a human antigen, anon-human animal antigen, a plant antigen, a bacterial antigen, a fungalantigen, a viral antigen, a parasitic antigen, or a cancer antigen.

In related embodiments, the immunogenic composition comprises thepolynucleotide adjuvant composition and a rabies antigen.

In certain embodiments, the antigens may be purified from a naturalsource, synthesized by means of solid phase synthesis, or may beobtained means of recombinant genetics. The antigen may comprise aprotein fragment comprising one or more immunogenic regions of themolecule. Antigens can also be provided by whole cells or microorganisms(e.g. whole viral particles), which may be live, attenuated, ortruncated, or killed.

In other embodiments, the antigens include one or more agents frominfectious agents, a plant antigen, cancer, allergenic agents and otherhuman antigen such as for developing autoimmune diseases. In otherembodiments, the antigens include one or more infectious agents from anyof the virus, bacteria, Mycobacterium, fungal, and parasites.

The polynucleotide adjuvant composition of the present invention canalso be utilized to enhance the immune response against antigensproduced by the use of DNA vaccines. The DNA sequences in these vaccinescoding for the antigen can be either “naked” or contained in a deliverysystem, such as liposomes.

In still other related embodiments the rabies antigen is selected fromhuman diploid cells vaccine (HDCV), or hamster kidney cell inactivatedpurified rabies vaccine (HKC-IPRV), or hamster kidney cell inactivatedcrude rabies vaccine (HKC-ICRV), or purified vero cell rabies vaccine(PVRV), or purified chicken embryo cell (PCEC), or purified duck embryovaccine (PDEV), or hamster kidney cell inactivated purified rabiesantigen (HKC-IPRA) or hamster kidney cell inactivated crude rabiesantigen (HKC-ICRA).

In one aspect of particular interest, the invention provides for animmunogenic composition for enhancing the antigenicity of an antigeniccompound comprising the polynucleotide adjuvant composition that iscapable of eliciting an antigen specific Cell mediated immune response.

In one aspect of particular interest, the invention provides for animmunogenic composition for enhancing the antigenicity of an antigeniccompound comprising the polynucleotide adjuvant composition that iscapable of eliciting an antigen specific B cell immune response.

In one aspect of particular interest, the invention provides for animmunogenic composition for enhancing the antigenicity of an antigeniccompound comprising the polynucleotide adjuvant composition that iscapable of eliciting a combined T cell and B cell antigen specificimmune response.

In one aspect of particular interest, the invention provides for animmunogenic composition for enhancing the antigenicity of a compoundcomprising the polynucleotide adjuvant composition and a hamster kidneycell inactivated purified rabies antigen, where the presence of therabies antigen should reach a minimum quantity, such as more than 1International Units (IU).

In related embodiments, the immunogenic composition comprises thepolynucleotide adjuvant composition and hamster kidney cell inactivatedpurified rabies antigen where the presence of the rabies antigen shouldreach a minimum quantity, such as more than 0.25 International Units, ismore than 0.5 International Units, is more than 1.2 International Units,is more than 1.4 International Units, is more than 1.6 InternationalUnits, is more than 1.8 International Units, is more than 2.0International Units, is more than 2.2 International Units, is more than2.4 International Units, is more than 2.6 International Units, is morethan 2.8 International Units, is more than 3.0 International Units, ismore than 3.2 International Units, is more than 3.4 International Units,is more than 3.6 International Units, is more than 3.8 InternationalUnits, or is more than 4.0 International Units.

In one aspect of particular interest, the invention provides for animmunogenic composition for enhancing the antigenicity of a compoundcomprising the polynucleotide adjuvant composition and a hamster kidneycell inactivated purified rabies antigen where the presence of theadjuvant and the rabies antigen is in a ratio of about 1 to 1.

In related embodiments, the immunogenic composition comprises thepolynucleotide adjuvant composition and a hamster kidney cellinactivated purified rabies antigen where the presence of the adjuvantand the rabies antigen is in a ratio of less than 1 to 10, of about 1 to9, of about 1 to 8, of about 1 to 7, of about 1 to 5, of about 1 to 4,of about 1 to 3, of about 1 to 2, of about 2 to 1, of about 3 to 1, ofabout 4 to 1, of about 5 to 1, of about 6 to 1, of about 7 to 1, ofabout 8 to 1, of about 9 to 1, of about 10 to 1, of greater than 10 to1.

In one aspect of particular interest, the invention provides for anadjuvant composition or immunogenic composition wherein the immunogeniccomposition, or the adjuvant composition contained in the immunogeniccomposition, is in a solid or liquid form or in solution or insuspension.

In one aspect of particular interest, the invention provides for anadjuvant composition or immunogenic composition comprising an adjuvantcomposition wherein the adjuvant composition or the immunogeniccomposition is freeze-dried.

In related embodiments the invention provides for a kit comprising theadjuvant composition and an antigenic compound.

In one aspect of particular interest, the invention provides for the useof a polynucleotide adjuvant composition for the preparation of amedicament for enhancing the immunogenic response of a host.

In one aspect of particular interest, the invention provides for amethod for enhancing immune responses to an antigenic compound,comprising administering to a host an immunogenic composition forenhancing the antigenicity of an antigenic compound comprising thepolynucleotide adjuvant composition.

In related embodiments, the method of administrating to a host theimmunogenic composition can be by one way selected from a groupincluding parenteral injection, intramuscular injection, intraperitonealinjection, intravenous injection, subcutaneous injection, inhalation,rectal delivery, vaginal delivery, nasal delivery, oral delivery,opthamalical delivery, topical delivery, transdermal delivery orintradermal delivery.

In one aspect of particular interest, the invention provides for amethod for enhancing immune responses to an antigenic compound,comprising administering to a host an immunogenic composition forenhancing the antigenicity of an antigenic compound comprising thepolynucleotide adjuvant composition wherein the host is human.

In one aspect of particular interest, the invention provides for amethod for enhancing immune responses to an antigenic compound,comprising administering to a host an immunogenic composition forenhancing the antigenicity of an antigenic compound comprising thepolynucleotide adjuvant composition wherein the host is an animal.

These and other features and advantages of the invention will becomeapparent from the following detailed description of preferredembodiments thereof in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the relative molecular weight for samples of Av-PICKCa andPIKA

FIG. 2 shows that PIKA induces a dose dependent production of a specificinterferon-gamma cytokine.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

The present invention may be understood more readily by reference to thefollowing detailed description of certain embodiments of the inventionand the Examples included herein.

Throughout this application, where publications are referenced, thedisclosures of these publications are hereby incorporated by reference,in their entireties, into this application in order to more fullydescribe the state of art to which this invention pertains.

Before the present invention is further described, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, the preferredmethods and materials are now described. All publications mentionedherein are incorporated herein by reference to disclose and describe themethods and/or materials in connection with which the publications arecited.

It must be noted that as used herein and in the appended claims, thesingular forms “a,” “and,” and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “atext” includes a plurality of such texts and reference to “the segment”includes reference to one or more segments and equivalents thereof knownto those skilled in the art, and so forth. It is further noted that theclaims may be drafted to exclude any optional element. As such, thisstatement is intended to serve as antecedent basis for use of suchexclusive terminology as “solely,” “only” and the like in connectionwith the recitation of claim elements, or use of a “negative”limitation.

DEFINITIONS OF TERMS

Prior to setting forth details of the present invention it may be usefulto an understanding thereof to set forth definitions of several termsthat are used herein.

The term “adjuvant,” as used herein, refers to any substance or mixtureof substances that increases or diversifies the immune response of ahost to an antigenic compound. Specifically:

-   -   1. The term “PICKCa” generally refers to a composition of poly        I:C, kanamycin and calcium irrespective of particular physical        and immunogenic properties.    -   2. “Av-PICKCa” refers to a form of PICKCa used commercially as        an antiviral drug.    -   3. “PIKA” refers to a composition of the invention comprising        poly I:C, an antibiotic (e.g., kanamycin), and a positive ion        (e.g., calcium), where the PIKA is characterized by physical        characteristics (e.g., molecular weight, size, and the like as        described herein) such that upon administration, PIKA exhibits        characteristics of an adjuvant with reduced adverse side effects        (e.g., reduced toxicity) relative to, for example, PICKCa and        greater potency (e.g., stimulates an enhanced immune response)        relative to, for example, Av-PICKCa.

“PIC-containing molecule” or “PIC-containing compound” refers to,without limitation, PIC, which may be optionally complexed or otherwisecombined with at least one or both of an antibiotic (e.g., kanamycin)and a positive ion (e.g., calcium) present in a composition containingthe PIC-containing molecule.

“Heterogeneous” as used herein in the context of the adjuvantcompositions of the invention indicates that components of thecomposition, e.g., the PIC-containing molecules, are not uniform withrespect to a physical characteristic of molecular weight, size, or both.

The term “animal” includes humans and all domestic and wild mammals andfowl, including, without limitation, cattle, horses, cows, swine, sheep,goats, dogs, cats, rabbits, deer, mink, chickens, ducks, geese, turkeys,game hens, and the like.

The term “antibody” includes polyclonal and monoclonal antibodies, aswell as antigenic compound binding fragments of such antibodiesincluding Fab, F(ab′)₂, Fd, Fv fragments, and single chain derivativesof the same. In addition, the term “antibody” includes naturallyoccurring antibodies as well as non-naturally occurring antibodies,including, for example, chimeric, bifunctional and humanized antibodies,and related synthetic isoforms.

As used herein, the term “antigenic compound” refers to any substancethat can be recognized by the immune system (e.g., bound by an antibodyor processed so as to elicit a cellular immune response) underappropriate conditions.

An “antigen” refers to a substance, including compositions in the formof a vaccine where the vaccine itself comprises an antigenic compoundand may or may not comprise an adjuvant other than PIKA, which whenadministered by an appropriate route (e.g., parenterally), induces animmune response, for example, the formation of antibodies, includingantibodies that specifically bind the antigen. Two of the characteristicfeatures of antigens are their immunogenicity, that is, their capacityto induce an immune response in vivo, and their antigenicity, that istheir capacity to be selectively recognized by the antibodies whoseorigins are the antigens.

The terms “cell-mediated immunity” and “cell-mediated immune response”are meant to refer to the immunological defense provided by lymphocytes,such as that defense provided by T cell lymphocytes when they come intoclose proximity to their victim cells. A cell-mediated immune responsenormally includes lymphocyte proliferation. When “lymphocyteproliferation” is measured, the ability of lymphocytes to proliferate inresponse to a specific antigen is measured. Lymphocyte proliferation ismeant to refer to B cell, T-helper cell or cytotoxic T-lymphocyte (CTL)cell proliferation.

An “effective amount of an antigenic compound” refers to an amount ofantigenic compound which, in optional combination with an adjuvant, willcause the subject to produce a specific immunological response to theantigenic compound.

The expression “enhanced immune response” or similar means that theimmune response is elevated, improved or enhanced to the benefit of thehost relative to the prior immune response status, for example, beforethe administration of an immunogenic composition of the invention.

The terms “humoral immunity” and “humoral immune response” refer to theform of immunity in which antibody molecules are produced in response toantigenic stimulation.

The term “immune response” refers to any response to an antigeniccompound by the immune system of a vertebrate subject. Exemplary immuneresponses include, but are not limited to cellular as well as local andsystemic humoral immunity, such as CTL responses, includingantigen-specific induction of CD8+ CTLs, helper T-cell responsesincluding T-cell proliferative responses and cytokine release, andB-cell responses including antibody response.

The term “eliciting an immune response” is used herein generally toencompass induction and/or potentiation of an immune response.

The term “inducing an immune response” refers to an immune response thatis, stimulated, initiated, or induced.

The term “potentiating an immune response” refers to a preexistingimmune response that is improved, furthered, supplemented, amplified,enhanced, increased or prolonged.

The term “Poly I:C” or “PIC” refers to a composition containingpolyriboinosinic and polyribocytidylic nucleic acids, which may also bereferred to as polyinosinic acid-polycytidylic acid, respectively.

The term “immunogenic amount” refers to an amount of antigenic compoundsufficient to stimulate an immune response, when administered with thecomposition of the invention, as compared with the immune responseobserved in the absence of the polynucleotide adjuvant.

The term “immunopotentiating amount” refers to the amount of theadjuvant needed to effect an increase in antibody titer and/or cellmediated immunity when administered with an antigenic compound in acomposition of the invention, as compared with the increase in antibodyand/or cell mediated immunity level observed in the absence of thepolynucleotide adjuvant.

As used herein, the term “mixing” includes any method to combine thecomponents of the composition; such methods include, but are not limitedto, blending, dispensing, dissolving, emulsifying, coagulating,suspending, or otherwise physically combining the components of thecomposition.

A “pharmaceutically acceptable salt” of a compound means a salt that ispharmaceutically acceptable and that possesses the desiredpharmacological activity of the parent compound. Such salts include: (1)acid addition salts, formed with inorganic acids such as hydrochloricacid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, andthe like; or formed with organic acids such as acetic acid, propionicacid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvicacid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid,fumaric acid, tartaric acid, citric acid, benzoic acid,3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid,methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid,2-hydroxyethanesulfonic acid, benzenesulfonic acid,4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid,4-toluenesulfonic acid, camphorsulfonic acid, glucoheptonic acid,4,4′-methylenebis-(3-hydroxy-2-ene-1-carboxylic acid), 3-phenylpropionicacid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuricacid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylicacid, stearic acid, muconic acid, and the like; or (2) salts formed whenan acidic proton present in the parent compound either is replaced by ametal ion, e.g., an alkali metal ion, an alkaline earth ion, or analuminum ion; or coordinates with an organic base such as ethanolamine,diethanolamine, triethanolamine, tromethamine, N-methylglucamine, andthe like.

The term “treatment” covers any treatment of a disease in a vertebrateanimal, particularly a human, and includes: (i) preventing the diseasefrom occurring in a subject which may be predisposed to the disease buthas not yet been diagnosed as having it; (ii) inhibiting the disease,i.e., arresting its development; or (iii) relieving the disease, i.e.,causing regression of the disease.

The term “unit dosage form” as used herein refers to physically discreteunits suitable as unitary dosages for human and animal subjects, eachunit containing a predetermined quantity of compounds of the presentinvention calculated in an amount sufficient to produce the desiredeffect in association with a pharmaceutically/physiologically acceptablediluent, carrier or vehicle.

OVERVIEW OF THE INVENTION

The present invention is directed to compounds and methods useful forthe enhancement of an immune response, which may be humoral and/orcell-mediated, in a human, animal or cell culture. In general thecomposition comprises of an immunogenic composition containing anadjuvant. The presence of the adjuvant enhances or modifies the immuneresponse. Thus, the humoral and/or cell-mediated immune responses aremore effective with the presence of the adjuvant. Furthermore, theadjuvant may alter the quality of the immune response by affecting thesubclasses (isotypes) of immunoglobulins and cytokines produced.

The key characteristics of the adjuvant are its ability to stimulate adesired level and type of immune response without inducing adverse sideeffects. There are currently only a limited number of adjuvants approvedfor human use that have such a combination of characteristics. Thesafety standards for immunogenic substances and particularly vaccinesare strict and rigorously enforced. Therefore, a significant constraintfor the development of a successful adjuvant is the development of aproduct that is sufficiently potent so as to elicit an appropriateimmune response while not inducing adverse side effects.

The preferred embodiment of the invention is a polynucleotide adjuvantwherein the polynucleotide is polyriboinosinic-polyribocytidylic acid(PIC). PIC alone has shown to be an effective adjuvant but exhibits anunacceptable safety profile and is unstable in human and primates. Thecurrent invention provides a composition of PIC combined with anantibiotic and positive ion that enhances the desired immunogenicattributes of an adjuvant while improving the safety and stabilityprofile.

The present invention is further based on the discovery that thephysical and biological characteristics of the PIKA molecules of theadjuvant composition influence the characteristics of the immuneresponse and adverse side effects. In the course of investigativeresearch studies it was unexpectedly discovered that by adjustingcertain characteristics of the polynucleotide adjuvant it becomes moreor less potent and/or more or less toxic in ways that are furtherdescribed below. Therefore by defining the composition of the adjuvantin terms of its physical characteristics it is possible to describe moreprecisely the attributes of the adjuvant composition that provides apreferable immunogenic response and preferable safety/stability profile.

The adjuvant of the current invention, referred to herein forconvenience as the PIKA adjuvant, is therefore fully defined by acombination of its chemical composition plus the fundamental physicalattributes of the molecules that make up the adjuvant. Thus theparticular form of PIKA that exhibits significantly superior immunogenicproperties while being safe to use in animals and humans is best definedby one or more, usually a combination of, specific attributes including;composition, molecular weight, molecular size, concentration, and pH.

PIKA generally comprises a polynucleotide, an antibiotic, and a positiveion, where the polynucleotide may be polyriboinosinic-polyribocytidylicacid (PIC), and the antibiotic an aminoglycoside (e.g., kanamycin,streptomycin, tobramycin), neomycin, an anthracycline, butirosinsulfate, a gentamicin, hygromycin, amikacin, dibekacin, nebramycin,metrzamide, puromycin, or streptozocin, and the ion is calcium, cadmium,lithium, magnesium, cerium, cesium, chromium, cobalt, deuterium,gallium, iodine, iron, or zinc.

The “aminoglycoside” antibiotics refer to antibiotics whose structurecontains amino sugars attached to an aminocyclitol ring (hexose nucleus)by glycosidic bonds. Aminoglycoside antibiotics are derived from variousspecies of Streptomyces and Micromonospora or are producedsynthetically. For example, kanamycin is an aminoglycoside antibioticobtained from the soil bacterium Streptomyces Kanamycetics, used in thetreatment of various infections, especially those caused byGram-negative bacteria.

The PIKA composition is manufactured through the mixing of polyinosinicacid, polycytidylic acid, an antibiotic and the source of a positive ionin a sodium chloride/phosphate buffer solution that has a pH between pH6and pH8. The polyinosinic acid and polycytidylic acid are generallyprovided at a concentration of 0.1 to 10 mg/ml, preferably 0.5 to 5mg/ml and more preferably 0.5 to 2.5 mg/ml. The hyperchromicity valueshould be greater than 10%, preferably greater than 15% and morepreferably greater than 20%. The preparation of the PIC and thecombination with the kanamycin and calcium is preferably conducted underquality standards consistent with international Good ManufacturingProcess.

In certain embodiments of the present invention, the kanamycin in thepolynucleotide adjuvant composition may be used together with orsubstituted by one or more antibiotics selected from the group includingtobramycin, anthracyclines, butirosin sulfate, gentamicins, hygromycin,amikacin, dibekacin, nebramycin, metrzamide, neomycin, puromycin,streptomycin and streptozocin. The antibiotic (e.g., Kanamycin or thelike) in the polynucleotide adjuvant composition of the invention isgenerally provided at a concentration of from about 10 to 100,000units/ml, preferably from about 100 to 10,000 units/ml, and morepreferably from about 500 to 5,000 units/ml.

In certain embodiments of the present invention, the polynucleotideadjuvant composition further comprises a positive ion (cation), usuallya divalent cation, normally a cation of an alkali metal. The positiveion is generally provided in the composition of the invention as asource of positive ions such as a salt or complex, e.g., an organic orinorganic salt or complex, usually an inorganic salt or organic complex.Exemplary positive ions include, but are not necessarily limited to,calcium, cadmium, lithium, magnesium, cerium, cesium, chromium, cobalt,deuterium, gallium, iodine, iron, or zinc.

The positive ion (e.g. calcium) can be provided in the composition ofthe invention at a concentration in the range of from about 10 umol to10 mmol/ml, preferably from about 50 umol to 5 mmol/ml, and morepreferably from about 100 umol to 1 mmol/ml.

As noted above, the positive ion can be provided in the form of anysuitable salt or organic complex, including, but not necessarily limitedto chloride, fluoride, hydroxide, phosphate, or sulfate salts. Forexample, where the positive ion is calcium, the ion can be in the formof calcium carbonate, calcium chloride, calcium fluoride, calciumhydroxide, calcium phosphates, or calcium sulfate.

Where the positive ion in the adjuvant composition of the invention iscalcium, it can be in combination with or substituted by other positiveions, including cadmium, lithium, magnesium, cerium, cesium, chromium,cobalt, deuterium, gallium, iodine, iron, and zinc, wherein the ions canbe in the form of inorganic salts or organic complexes.

The resulting composition is further transformed into PIKA through anadditional manufacturing process that involves the isolation ofmolecules of a defined molecular size and/or weight. The separation ofpolynucleotide molecules of particular characteristics using filtration,chromatography, thermal treatment, centrifugal separation,electrophoresis, and similar methods that are standard processes areknown to those skilled in the art.

In certain embodiments of the present invention, the polynucleotideadjuvant composition is further defined by the physical attribute ofmolecular weight. In the course of investigation it was surprisinglyfound that there is a positive correlation between molecular weight andthe efficacy of the polynucleotide adjuvant composition. The observedlevel of potency of an immunogenic composition containing thepolynucleotide adjuvant composition, including the ability to elicit theproduction of immunoglobulins and cytokines, increases as the molecularweight of the polynucleotide adjuvant composition increases. Themolecular weight of the polynucleotide adjuvant can be determined byargarose gel electrophoresis as described in Example 1.

As illustrated in the Examples section below, the inventor hasdiscovered that vaccine compositions containing a PIKA adjuvant of avariety of molecular weights exhibited a direct correlation betweenmolecular weight and antigen specific protective potency (see Example2). Likewise, the inventor has discovered that there is a directcorrelation between the molecular weight of PIKA adjuvant compositionsand the ability to elicit the production of interferon-gamma whenadministered to a host in combination with a rabies antigen (see Example3).

The inventor further identified, during human trials in 1996 in Chinausing a rabies vaccine with an adjuvant comprising PICKCa of aparticularly high molecular weight specification, that the resultingcomposition was surprisingly shown to have an unacceptable level ofadverse side effects. The results from the clinical trial in 1996 thathave not previously been published are presented in Example 4. Theresearch into the molecular weight is presented in Examples 5 and 6. Thetrial was conducted under the jurisdiction of the Chinese Food and DrugAdministration. Thus the adjuvant would not have been administered tohumans in a controlled clinical trial environment if such side effectshad been anticipated based on the knowledge at that time.

The inventor has found that PIKA adjuvant compositions of the inventionin pre-clinical studies with molecular weights up to 1.0×10⁶ andcompositions of vaccines including PIKA adjuvant compositions withmolecular weights of up to 5.5×10⁵ have demonstrated a wide safetymargin in specific toxicity tests (see Example 7). PIKA with a maximummolecular weight of 1.2×10⁶ has been successfully used in pre-clinicalresearch (see Example 3). Further research conducted by the inventordemonstrates the safety of PIKA when used in conjunction with an antigencompound in the form of a vaccine (see Example 8).

Results from a subsequent experiment conducted by the inventor in Chinain 2002 also demonstrate that the use of PIKA provides a safe andeffective adjuvant in humans. The results of this experiment, notpreviously published, are presented in Example 9.

Based on the above observations, the preferred embodiment of PIKAtherefore comprises molecules having physical characteristics ofmolecular weight and/or size that provide benefit from the increase inpotency and efficacy while providing an adequate degree of safety marginso as not to induce any adverse side effects. Molecules present inAv-PICKCa, at the lower end of the molecular weight range, may beeffective as an antiviral composition but are significantly lesseffective than the molecular composition of PIKA when used as anadjuvant in an immunogenic composition. Further, PIKA has been shown tohave a safety profile that is preferable to PICKCa.

One aspect of the current invention is thus the molecular weight ofPIKA, the composition of the invention.

The inventive composition of PIKA generally comprises a collection orpopulation of molecules, where the molecules have physicalcharacteristics of, for example, molecular weight and/or size, thatprovide for a desired effect in eliciting an immune response while,preferably, mitigating or avoiding adverse side effects (such as thoseassociated with the administration of PICKCa). Generally, the moleculesof PIKA are heterogeneous for molecular weight and/or size.

As generally used herein and unless specifically indicated otherwise,PIKA, the adjuvant composition of the invention, includes PIC which maybe complexed with an antibiotic (e.g., kanamycin) and a positive ion(e.g., calcium). The molecules in PIKA are heterogeneous in molecularweight (e.g., as assessed by Daltons) or size (e.g., as assessed bysedimentation coefficient).

Where a range is used in reference to a heterogeneous characteristic ofPIKA molecules (e.g., molecular weight or size), reference to such arange herein indicates the approximate lower and upper limits of themolecular weights or sizes of the PIKA molecules in the composition, butdoes not imply or intend that the composition contains a PIKA moleculethat has a molecular weight or size that is representative of everymolecular weight or size within the range. Thus, for example, amolecular weight range of from about 66,000 to 1,200,000 Daltonsindicates that PIKA molecules of about 66,000 Daltons and about1,200,000 Daltons are contained in the composition, but there is norequirement that PIKA molecules of 88,000 Daltons be present in thecomposition (although, indeed, such may be present).

Where a physical characteristic of the PIKA molecules in the inventivecomposition is defined by a range of molecular weights, the PIKAmolecules are heterogeneous for molecular weight, wherein the molecularweight range is from about 300,000 to 660,000 Daltons, from about300,000 to 1,200,000 Daltons, from about 66,000 to 660,000 Daltons, orfrom about 66,000 to 1,200,000 Daltons.

The invention also contemplates compositions having PIKA moleculesheterogeneous for molecular weight, where the molecular weight range isfrom about 300,000 to 2,000,000 Daltons, from about 300,000 to 4,000,000Daltons, from about 500,000 to 1,000,000 Daltons, from about 1,000,000to 1,500,000 Daltons, from about 1,500,000 to 2,000,000 Daltons, fromabout 2,000,000 to 2,500,000 Daltons, from about 2,500,000 to 3,000,000Daltons, from about 3,000,000 to 3,500,000 Daltons, from about 3,500,000to 4,000,000 Daltons, from about 4,000,000 to 4,500,000 Daltons, or fromabout 4,500,000 to 5,000,000 Daltons. PIKA molecules having molecularweights at the upper and lower limits of these ranges, as well as withinthese ranges, are present in the composition.

Where a physical characteristic of the PIKA molecules in the inventivecomposition is defined by average molecular weight, the PIKA moleculescan have an average molecular weight equal to or greater than 150,000Daltons, equal to or greater than 250,000 Daltons, equal to or greaterthan 350,000 Daltons, equal to or greater than 500,000 Daltons, equal toor greater than 650,000 Daltons, equal to or greater than 750,000Daltons, equal to or greater than 1,000,000 Daltons, equal to or greaterthan 1,200,000 Daltons, equal to or greater than 1,500,000 Daltons, orequal to or greater than 2,000,000 Daltons.

Where a physical characteristic of the PIKA molecules in the inventivecomposition is defined by a sedimentation coefficient, which is ameasure of molecular weight and size, the PIKA molecules can have asedimentation co-efficient greater than 9, or greater than about 12, orgreater than about 13.5, or greater than 15, or greater than 16, orgreater than 17, or greater than 18, or greater than 19, or greater than20, or greater than 21, or greater than 22, or greater than 25, orgreater than 30.

In some embodiments, the invention provides a polynucleotide adjuvantcomposition comprising polyriboinosinic-polyribocytidylic acid (PIC),kanamycin and calcium wherein the composition excludes a detectableamount of molecules which have a molecular weight about or below 30,000Daltons, about or below 40,000 Daltons, about or below 50,000 Daltons,about or below 60,000 Daltons, about or below 70,000 Daltons, about orbelow 80,000 Daltons, about or below 90,000 Daltons, about or below100,000 Daltons, about or below 150,000 Daltons, about or below 200,000Daltons, about or below 250,000 Daltons, about or below 300,000 Daltons,about or below 350,000 Daltons, about or below 400,000 Daltons, about orbelow 450,000 Daltons, about or below 500,000 Daltons, about or below600,000 Daltons, about or below 700,000 Daltons, about or below 800,000Daltons, about or below 900,000 Daltons, or about or below 1,000,000Daltons. In this embodiment, exclusion of such lower molecular weightmolecules is particularly of interest to an extent that such excludedmolecules have no significant immunogenic effect.

PIKA comprising molecules of a molecular weight of up to 1.0×10⁶ Daltonshas been shown by the inventor to be safe in animals in specifictoxicity tests (see Example 7). PIKA comprising molecules of a molecularweight of up to 1.2×10⁶ Daltons has been safely used in pre-clinicalstudies (see Example 3). PIKA has also been shown to be safe when usedin a immunogenic composition (see Example 8). Such a composition of PIKAprovides benefits in terms of effectiveness. PIKA comprising moleculesof a molecular weight up to 6.6×10⁵ Daltons also elicits an effectiveimmune response with a wider margin of safety when used in humans andanimals. Raising the molecular weight of the smallest molecules presentto 6.6×10⁵ Daltons and preferably to 3.0×10⁵ Daltons, improves theeffectiveness of the adjuvant without compromising safety standards.

It has been further discovered that the concentration of thepolynucleotide adjuvant composition may impact the molecular weight ofthe molecules contained in the composition. The molecular weight ofPICKCa has been shown to increase as concentration of the adjuvantcomposition (see Example 5) increases. The inventor has observed thatincreasing concentration of the polynucleotide adjuvant may result inthe coalescence (or aggregation) of the PICKCa molecules, resulting inmolecules with a large molecular weight. This process has been shown tobe irreversible. Thus the subsequent dilution of the polynucleotideadjuvant composition in a suitable medium does not result in a reductionin molecular weight of the adjuvant molecules. As observed in Example 6,when the concentrated large molecular form of polynucleotide adjuvantcomposition is combined with the rabies antigen, the result is acomposition that retains its high molecular weight range. A rabiesvaccine formed in this way demonstrated adverse side effects in humanclinical trials (see Example 4).

The PIKA composition of the invention can be provided in anyphysiologically acceptable buffer may be used herein, but phosphatebuffers are preferred. Other acceptable buffers such as acetate, tris,bicarbonate, carbonate, or the like may be used as substitutes forphosphate buffers.

The pH of the aqueous component will preferably be between 4.0 and 10.0though it is preferable to adjust the pH of the system from 6 to 8.5where that pH does not significantly reduce the stability of othercomposition components and is not otherwise physiologically unsuitable.In certain embodiments the aqueous portion of the immunogeniccomposition is buffered saline. When these compositions are intended forparenteral administration, it is preferable to make these solutions sothat the tonicity, i.e., osmolality, is essentially the same as normalphysiological fluids in order to prevent post-administration swelling orrapid absorption of the composition because of differential ionconcentrations between the composition and physiological fluids.

The quantity of buffered saline employed in these compositions will bethat amount necessary to bring the value of the composition to unity.That is, a quantity of buffered saline sufficient to make 100% will bemixed with other components in order to bring the composition to volume.

In certain embodiments, the antigens may be purified from a naturalsource, synthesized by means of solid phase synthesis, or may beobtained by means of recombinant genetics. The antigen may comprise aprotein fragment comprising one or more immunogenic regions of themolecule. Antigens can also be provided by whole cells or microorganisms(e.g., whole viral particles), which may be live, attenuated, truncated,or killed.

In other embodiments, the antigens include one or more agents frominfectious agents, a plant antigen, cancer, allergenic agents and otherhuman antigen, such as for developing autoimmune diseases. In otherembodiments, the antigens include one or more infectious agents from anyof the virus, bacteria, Mycobacterium, fungal and parasites.

The polynucleotide adjuvant composition of the present invention canalso be utilized to enhance the immune response against antigensproduced by the use of DNA vaccines. The DNA sequences in these vaccinescoding for the antigen can be either “naked” or contained in a deliverysystem, such as liposomes.

In certain embodiments, the polynucleotide adjuvant composition can beused in combination with vaccines. It does not matter whether thevaccine contains adjuvants or not. Vaccines classes included areanti-infectious diseases, anti cancer, anti-allergy, anti-autoimmunediseases, and immunocontraception.

The invention also contemplates use of the polynucleotide adjuvant ofthe invention in combination with any suitable rabies antigen.

In certain embodiments, the rabies antigen can be an inactivated cruderabies antigen such as a hamster kidney cell inactivated crude rabiesantigen (HKC-ICRA) or an inactivated purified rabies antigen such as ahamster kidney cell inactivated purified rabies antigen (HKC-IPRA).

In certain embodiments, the polynucleotide adjuvant composition can beused with a rabies vaccine. Suitable rabies vaccines are commerciallyavailable or in research development including inactivated, subunit,recombinant and peptide vaccines such as human diploid cells vaccine(HDCV), or hamster kidney cell inactivated purified rabies vaccine(HKC-IPRV), or hamster kidney cell inactivated crude rabies vaccine(HKC-ICRV), or purified vero cell rabies vaccine (PVRV), or purifiedchicken embryo cell (PCEC), or purified duck embryo vaccine (PDEV).However, not all of the rabies vaccines elicit a cell-mediated immuneresponse which is important in pre- and post-exposure immunizations.When the polynucleotide adjuvant composition (e.g., PIKA) isadministered with the rabies vaccine, the immune responses inducedinclude; non-specific responses (e.g., increased functions ofmacrophages), humoral responses (e.g., increased specific antibodyproduction), and cell-mediated responses (e.g., production of cytokinesincluding interferon and interleukin-2).

In certain embodiments, the invention provides for a kit comprising thepolynucleotide adjuvant and an antigenic compound.

An immunogenic composition including PIKA is able to induce a specificimmune response in two ways: i) humoral-mediated immunity, whichincludes B cell stimulation and production of antibodies orimmunoglobulins (other cells are also involved in the generation of anantibody response, e.g. antigen-presenting cells (APCs, includingmacrophages), and helper T cells (Th1 and Th2)), and ii) cell-mediatedimmunity, which generally involves T cells including cytotoxic Tlymphocytes (CTLs), although other cells are also involved in thegeneration of a CTL response (e.g., Th1 and/or Th2 cells and APCs).Methods for assessing humoral and/or cellular immune response in anindividual are well known in the art. (see Examples 10, 11, 12 and 13).

Furthermore, the polynucleotide adjuvant composition may alter thequality of the immune response by affecting the subclasses (isotypes) ofimmunoglobulins produced (IgG1, IgG2, IgG3, and IgG4 for human IgGs;IgG1, IgG2a, IgG2b, and IgG3 for mouse IgGs), as well as theiraffinities.

A response regulated by Th1 cells in mice will induce IgG1, IgG2a, IgG2band to a lesser extent IgG3, and also will favor a cell mediated immuneresponse to an antigen. If the IgG response to an antigen is regulatedby Th2 type cells, it will predominantly enhance the production of IgGIand IgA.

NIH potency tests using a composition of the PIKA adjuvant and a hamsterkidney cell inactivated purified rabies antigen surprisingly showed thatimmunogenic potency of the composition requires a minimum presence ofrabies antigen (see Example 14). The potency of the compositionincreases rapidly relative to the presence of additional rabies antigenin excess of 1 IU of antigen. Thus the rate of increase in potency ofthe composition was observed to be greatest with around 1.5 IU to 2.5 IUof the rabies antigen present in the composition. The NIH potency testis described in: Laboratory Techniques in Rabies, Edited by F X Meslin,M M Kaplan H Koprowski, 4^(th) Edition, ISBN 92 4 1544 1.

Tests using a composition of the PIKA adjuvant and a hamster kidney cellinactivated purified rabies antigen demonstrated that the immunogenicpotency of the composition increased as the quantity of adjuvant presentexceeded the amount of antigen present. The potency increased when theratio of PIKA to hamster kidney cell inactivated purified rabies antigenwas increased with the preferred ratio being greater than 3:1. (seeExample 15).

The invention contemplates methods of use of the polynucleotide adjuvantof the invention with an antigen to, for example, elicit an antigenspecific humoral response and/or specific cellular (e.g., T cell)response in a subject. The immune response elicited may be a response toan antigen in a naïve subject, or may serve to enhance an existingimmune response (e.g., as in a booster).

In certain embodiments, the PIKA adjuvant composition and an immunogeniccomposition comprising the PIKA adjuvant and antigenic compound may befreeze-dried (lyophilized) for long term stability and storage in asolid form. The freeze-dried method is known to those skilled in theart. The reconstitution of the immunogenic composition containing PIKAand an antigenic compound demonstrated a sustained level ofeffectiveness (see Example 16).

The immunogenic composition may be prepared as an injectable, liquidsolution, suspension or emulsion. The preparation of formulations of adesired immunogenic composition is generally described in New Trends andDevelopments in Vaccines, edited by Voller et al., University ParkPress, Baltimore, Md., USA, 1978. The immunogenic composition of thepresent invention may be employed in such forms as capsules, liquidsolutions, emulsions, suspensions, or elixirs for oral administration,or sterile liquid forms such as solutions, emulsions, or suspensions.Any inert carrier is preferably used, such as saline, or phosphatebuffered saline, or any such carrier in which the compounds used in themethod of the present invention have suitable solubility properties foruse in the methods of the present invention.

The immunogenic composition of the present invention can be administeredto a subject using a variety of methods known in the art. In certainembodiments, the immunogenic composition can be delivered parenterally,by injection, such as intramuscular, intraperitoneal, intravenous, orsubcutaneous injection, or by inhalation. In other embodiments, theimmunogenic composition can be delivered rectally, vaginally, nasally,orally, opthamalically, topically, transdermally or intradermally. Whenthe mode of administration is by injection, the encapsulated antigeniccompound may stay at the injection site for up to two weeks, thusproviding a depot of antigen that will give sustained release orpulsatile release in vivo. Such a delivery system may allow single shotimmunogenic formulations to be produced for antigenic compounds thatwould otherwise require multiple injections to elicit an immuneresponse.

For parenteral administration in an aqueous solution, for example, thesolution should be suitably buffered if necessary and the liquid diluentfirst rendered isotonic with sufficient saline or glucose. Theseparticular aqueous solutions are especially suitable for intravenous andintraperitoneal administration. In this connection, sterile aqueousmedia which can be employed will be known to those of skill in the artin light of the present disclosure. Exemplary injection media which canbe used in the present invention include a buffer with or withoutdispersing agents and/or preservatives, and edible oil, mineral oil, codliver oil, squalene, mono-, di- or triglyceride, and a mixture thereof.

The exact amount of such compositions required will vary from subject tosubject, depending on the species, age, weight, and general conditionsof the subject, the severity of the disease, infection, or conditionthat is being treated or prevented, the particular compound used, itsmode administration, and the like. An appropriate amount may bedetermined by one of ordinary skill in the art using only routineexperimentation given the teachings herein. Following an initialadministration, subjects may receive one or several boosterimmunizations adequately spaced.

The above disclosure generally describes the present invention. Thefollowing examples will be of assistance to the understanding of thepresent invention. These examples are described solely for purposes ofillustration and are not intended to limit the scope of the invention.Changes in form and substitution of equivalents are contemplated ascircumstances may suggest or render expedient. Although specific termshave been employed herein, such terms are intended in a descriptivesense and not for purposes of limitation.

EXAMPLES Example 1 Determination of the Molecular Weight of PIKA andAv-PICKCa

This example illustrates how the molecular weight was determined for thePIKA adjuvant in comparison with Av-PICKCa.

Argarose gel electrophoresis is known to those skilled in the art, sothat only the particulars to this invention are described herein. Theargarose gel used in the present invention had a concentration of 1.5%argarose. The molecular markers were 100 bp DNA ladders from 100 bp to1000 bp corresponding to a range of molecular weight from 6.6×10⁴ to6.6×10⁵ Daltons. The loading samples were 4 ul at 1 mg/ml. FIG. 1 showsa representative picture of the result of the samples on the argarosegel following the teachings of this paragraph. The five (5) differentbatches tested showed a wide range of distribution of their molecularweights. The upper limits of their molecular weights ranged from 2.3×10⁵Daltons for Av-PICKCa to 5.28×10⁵ Daltons for PIKA.

Example 2 Immune Efficacy of PIKA Compared with Av-PICKCa

This example demonstrates the difference between the potency ofAv-PICKCa with a maximum molecular weight of 230,000 Daltons and samplesof PIKA with a maximum molecular weight of up to 528,000 Daltons.

Three batches of the PIKA adjuvant of different molecular weight and onebatch with molecules of molecular the weight corresponding to that ofAv-PIKA were combined with the hamster kidney cell inactivated purifiedrabies antigen (HKC-IPRA). The, resulting compositions were subjected tothe NIH efficacy test.

The NIH test is a rigorous and extensive comparative study between therabies vaccine under investigation and a standardized rabies vaccine.The vaccinated mice are infected with a strain of live rabies virus andtheir survival rate is measured. The different groups of mice areadministered with different dilutions of the rabies vaccine. Acomparison of the survival rates between the groups of mice exposed tothe experimental and standardized vaccine determines the potency of theexperimental vaccine (Laboratory Techniques in Rabies, Edited by F XMeslin, M M Kaplan H Koprowski, 4^(th) Edition, ISBN 92 4 1544 1).

The efficacy of each combined vaccine has been normalized in relation tothe standard, non-combined vaccine, where the efficacy of thenon-combined one was designated as 1, and the relative efficacy wasdesignated as the times by which the efficacy of a combined one hadincreased over the non-combined one. Table 1 summarizes the results. Asseen from Table 1, the higher the molecular weight of the PICKCaadjuvant, the higher the efficacy of increasing the titer of rabiesvaccine.

TABLE 1 Effects of the Molecular Weight on Rabies Vaccine PotencyAdjuvant's Upper Limit of Adjuvant Molecular Potency Type Antigen Sample# Weight ED₅₀ (IU/ml) PIKA HKC- 20000304 5.28 × 10⁵ 2.10 5.00 IPRA PIKAHKC- 20000907 4.62 × 10⁵ 2.00 3.98 IPRA PIKA HKC- 990202 3.96 × 10⁵ 1.983.80 IPRA Av- HKC- 000703 2.30 × 10⁵ 1.88 3.00 PICKCa IPRA HKC- Vaccine1.40 1.00 IPRA control

Example 3 Interferon Production Comparison Between PIKA and Av-PICKCa

This example demonstrates the difference in ability to elicit theproduction of interferon between samples of Av-PICKCa with a maximummolecular weight of 230,000 Daltons and samples of PIKA with a maximummolecular weight of up to 1,200,000 Daltons.

Two batches of PIKA with upper limits of molecular weight of 1.2×10⁶Daltons and 4.6×10⁵ Daltons were compared with a batch of Av-PICKCa withan upper limit of molecular weight of 2.3×10⁵ Daltons.

Compositions of the PIKA and Av-PICKCa were combined with hamster kidneycell inactivated purified rabies antigen (HKC-IRPA). The compositionswere injected subcutaneously into mice. After two hours, the interferonpresence in each mouse was determined. The general procedure for theinterferon measurement is known to those in the art. Briefly, in a96-well plate, each well was inoculated with L929 cells at 0.15 ml/wellwith about 30,000 cells. After three (3) days when the cells grew toconfluence, wells were added into sera samples (0.1 ml/well) wherein thesera were diluted by 1:20 to 1:640. Three wells were for each dilutedsample. The wells were incubated overnight at 37° C. The sera sampleswere washed away. Vesicular stomatitis virus VSV particles were used todetect the interferon production. Table 2 shows the interferonproduction induced by the mixtures. As seen from Table 2, the higher themolecular weight of the PIKA samples, the better the interferonproduction induced.

TABLE 2 The Relationship Between Molecular Weight and InterferonProduction Upper Range of Molecular HKC- PIKA:HKC- Titer of AdjuvantWeight IPRA IPRA Interferon Type Batch # Daltons Batch# Ratio ProductionPIKA 20010601 1.20 × 10⁶ 20001205 4:1 868.6 PIKA 200009-7 4.62 × 10⁵20001205 4:1 530.6 Av-  000703 2.30 × 10⁵ 20001205 4:1 46.4 PICKCa

Example 4 1996 Human Vaccine Clinical Trial (with Toxic Side Effects)

This example demonstrates that the PICKCa adjuvant when combined with avaccine generates an unacceptable level of side effects whenadministered for human use.

The objective of the study was to evaluate the safety and immuneresponse of a rabies vaccine comprising PICKCa adjuvant at aconcentration of 11.95 mg/ml and molar mass of 69,700 (note molar massis not equivalent to Daltons in this case, see Example 5) and a hamsterkidney cell inactivated crude rabies antigen (HKC-ICRA). The results andconclusions from the above clinical trial have not previously beenreleased into the public domain.

The 40 patients participating in the trial were divided into two groupsof 20 people. Each group received five (5) doses of 2 ml administeredintramuscularly on day 1, day 3, day 7 and day 30. One group receivedthe rabies antigen with the PICKCa adjuvant and the other group receivedthe rabies antigen with an alum adjuvant.

From a safety perspective, observations were made of body temperature,local, and systemic symptoms at 24 hours, 48 hours and 72 hours aftereach injection. The following observations were:

TABLE 3 Adverse effects after injection of HKC-ICRA with Alum or PICKCaNumber of Number with Side Effect Group Volunteers Adverse effect LocalPICKCa plus 20 6 HKC-ICRA Alum plus 20 2 HKC-ICRAx5 Systemic PICKCa plus20 4 HKC-ICRA Alum plus 20 0 HKC-ICRAx5

Systemic adverse effects included: fever (1), rash (2), joint pain (2),lymph node (1), throat edema (1). Local Adverse effects included: redskin at injection site (6)

Subsequent research by the inventor attributed the side effects observedto the molecular size of the molecules in the adjuvant (see Examples 5and 6).

Example 5 Relationship Between PICKCa Concentration and its MolecularWeight

This example demonstrates that increasing the concentration of thePICKCa adjuvant results in a composition with an increased molecularweight.

PICKCa can be made in different concentrations. It was hypothesized thatthe PICKCa as a complex of polymers would exist in different forms whenit was prepared in different concentrations. Laser light scattering wasused for this purpose. Laser light scattering has been broadly used todetermine weight-average molar mass (Mw) and radius of gyration (Rg).The instruments are commercially available and the process is known tothose skilled in the art. Table 4 shows that the observed molecularweight of PICKCa by laser light scattering correlated to itsconcentration.

TABLE 4 The Observed Molecular Weight by Laser Light ScatteringConcentration of PICKCa (mg/ml) Weight-average Molar Mass 11.95 6.97 ×10⁴ 2.00 7.30 × 10³ 1.00 2.00 × 10³

Example 6 Relationship Between Pre-Concentration of PICKCa and MolecularWeight of Vaccine

This example demonstrates a correlation between the increased molecularweight of the PICKCa adjuvant and the resulting molecular weight of thecomposition that includes the PICKCa adjuvant and a hamster kidney cellinactivated crude rabies antigen.

It was also suspected that the pre-combination concentration of PICKCasamples would affect the antigens in vaccines. Samples of PICKCa werecombined with a hamster kidney cell inactivated crude rabies antigen.Laser light scattering was used for this purpose. Laser light scatteringhas been broadly used to determine weight-average molar mass (Mw) andradius of gyration (Rg). The instruments are commercially available andthe process is known to those skilled in the art. Table 5 shows that anincrease of pre-combination concentrations of PICKCa resulted in anincrease of the Mw of rabies vaccines.

TABLE 5 Relationship Between Pre-combination Concentration of PICKCa andthe Mw of Rabies Vaccines Concentration of Weight-average PICKCa (mg/ml)Molar Mass Radius of Gyration 11.95 29.6 × 10⁴ 17.2 × 10² 4.00 22.2 ×10⁴ 15.0 × 10² 2.00 13.8 × 10⁴ 11.8 × 10² 1.00 5.60 × 10⁴ 7.55 × 10²1.00 5.29 × 10⁴ 6.50 × 10²

Example 7 PIKA Toxicity Test

This example demonstrates the safety characteristic of the PIKA adjuvantwhen there is a restriction on the maximum molecular weight.

A toxicity test was conducted in accordance with the provisions of ChinaNational Drug Standard (WS1-XG-050-2000). Briefly, five (5) mice with abody weight of about 18-22 grams are injected intravenously with 0.5ml/mouse of a sodium chloride solution containing 0.3 mg of a PIKAadjuvant having an upper molecular weight from about 525,000 to about1,000,000 Daltons. The injected mice are observed for 7 days and weighedat the end of the observation. Table 6 summarizes the results thatshowed that the molecular weight of the PIKA adjuvant could be as highas 1.0×10⁶ Daltons without obvious toxicity.

TABLE 6 PIKA Adjuvant Toxicity Test Upper Range of Status of Post-testMolecular Pre-test Amount of mice at body Weight bodyweight tail veinthe end weight of Batch # (Daltons) of mice (g) injection of test miceRemarks 20000304 5.25 × 10⁵ 18-19 0.5 ml/mouse Healthy 23-26Satisfactory 20010103 5.20 × 10⁵ 18-19 0.5 ml/mouse Healthy 22-25Satisfactory 20010816 5.20 × 10⁵ 18-19 0.5 ml/mouse Healthy 23-25Satisfactory 20010511 1.00 × 10⁶ 18-20 0.5 ml/mouse Healthy 24-26Satisfactory

Example 8 PIKA in Vaccine Composition Toxicity Study

The objective of this experiment is to validate the safety of the PIKAadjuvant.

The PIKA adjuvant (molecular weight 66,000 Daltons to 660,000 Daltons)was combined with hamster kidney cell inactivated purified rabiesantigen (HKC-IPRA) in a ratio of PIKA:HKC-IPRA of 4:1.

The vaccine composition of PIKA and HKC-IPRA was compared with acommercially available inactivated purified rabies vaccine (IPRV) thatincluded an alum adjuvant.

Mice were administered five (5) doses of the vaccine composition on day0, day 3, day 7, day 14, and day 28. The dose administered wasequivalent to approximately 300 times that of an adult human dose underthe normal human rabies immunization regime.

Results of the toxicity observations are presented in table 7 below:

TABLE 7 Safety Observations after Administration of the Rabies VaccineFormulations Effect Day 0 Day 3 Day 7 Day 14 Day 28 HKC-IPRA Allergy0/20 0/20 0/20 0/20 2/20 plus PIKA HKC-IPRA Death 0/20 0/20 0/20 0/200/20 plus PIKA IPRV Allergy 0/20 0/20 0/20 5/20 — (including Alum) IPRVDeath 0/20 0/20 0/20 2/20 7/20 (including Alum) Key: (Occurrenceobserved)/(Total number)

The conclusion drawn is that the PIKA/HKC-IPRA combination is safer thanthe commercially available IPRV.

Example 9 Safe Use of PIKA Adjuvant in Humans

In 2002, five (5) volunteers were immunized with a composition of PIKA(molecular weight 66,000 to 660,000 Daltons) and hamster kidney cellinactivated purified rabies antigen (HKC-IPRA). Volunteers wereadministered the vaccine composition on day 0, day 3, day 7, day 14, andday 30.

No local or systemic side effects were observed for any of the patientsafter each of the vaccinations.

The potency of the vaccine was measured using the standard NIH test withthe results presented in table 8 below:

TABLE 8 Rabies Vaccine Potency Observations Neutralizing Day ED50antibody IU/ml 0 0 0 14 >1.9 >1.84 45 2.35 5.17

Results indicate that the vaccine composition of PIKA and HKC-IPRAinduces a specific immune response and elicits the production ofprotective neutralizing antibodies.

Example 10 Post Exposure Test Cell Mediated Immunity

The post exposure test is the most definitive proof that the vaccine hasthe ability to eradicate pathogens from the host's body after infection.As such, it is an indication of the cell mediated immune responseinduced by the vaccine.

In the post exposure tests mice were infected with a wild strain ofrabies virus and subsequently inoculated with: a hamster kidney cellinactivated purified rabies antigen (HKC-IPRA) in combination with PIKAadjuvant (molecular weight range from 1.65×10⁵ to 1.2×10⁶ Daltons), orHKC-IPRA in combination with an aluminum hydroxide (alum) adjuvant, acommercially available purified vero-cell rabies vaccine (PVRV), orphosphate buffer solution (PBS). Results conclusively show that the PIKAadjuvant improved survival rates, see table 9.

TABLE 9 Post Exposure Challenge Test Pre-determined 80% Pre-determined50% Groups Death Dosage Death Dosage 9.1 Death Rate After Treatment PIKAplus HKC-IPRA  2/20 0/20 Alum plus HKC-IPRA 10/20 9/20 PVRV 16/20 3/20Control (PBS) 15/20 14/20  9.2 Survival Rate After Treatment PIKA plusHKC-IPRA 90.00% 100.00%  Alum plus HKC-IPRA 50.00% 55.00% PVRV 20.00%85.00% Control (PBS) 25.00% 30.00%

Mice infected with a subcutaneous injection of live rabies virus weretreated with vaccine at 6 hours, 1 day, 2 days, and 3 days afterinfection

Example 11 Antigen Specific Cell Mediated Immune ResponseInterferon-Gamma Production

The production of interferon-gamma is an indicator of cell mediatedimmunity activity.

In this experiment, blood samples were taken from two trial patients andtwo control individuals. The volunteer patients had been vaccinated withthe PIKA rabies vaccine, which contained PIKA (molecular weight rangefrom 66,000 to 660,000 Daltons) and hamster kidney cell inactivatedpurified rabies antigen (HKC-IPRA) vaccine 2.5 years before collectionof the blood samples.

Results in FIG. 2 illustrate the significant difference ininterferon-gamma produced by the two trial patients when compared withthe control individuals.

The isolated monocytes from the blood samples were incubated with thesame HKC-IPRA as was used in the original trial. After 3 days ofincubation, the cell-free supernatants were harvested and theinterferon-gamma in the supernatants was assayed by cytokine-specificELISPOT. A dose dependant effect was observed.

The conclusions from the above observation are:

-   -   the rabies vaccine that included the PIKA adjuvant of the        invention has the ability to induce the production of        interferon-gamma and by implication to elicit a cell mediated        immune response    -   the interferon-gamma response is specific (i.e., the response        was directed to the rabies antigen as opposed to a non-specific        reaction. If the interferon-gamma response were non-specific        there would be no variation in the level of interferon-gamma        production for the vaccinated patients' blood as the        concentration of antigen stimulant increased

Example 12 PIKA Efficacy Test

The object of this experiment is to demonstrate the PIKA's ability toelicit the production of interferon-gamma and interleukin 12 (IL-12).

Samples of splenocytes from normal healthy mice were incubated over aperiod of three days in the presence of PIKA (molecular weight rangefrom 66,000 to 660,000) in a clean environment. At the end of the periodthe level of cytokines in the supernatants were assayed with IL-12(p40)and interferon-gamma specific ELISA tests. The results of the experimentare presented in the table 10 below:

TABLE 10 In-vitro Test for Cytokine Production PIKA IFN-gamma IL-12P40ug/ml pg/ml pg/ml 0 3 0 0.4 23 91 2 22 98 10 30 134 50 179 186 100 559N/A 250 1340 N/A

The conclusion from the experiment above is that PIKA elicits a dosedependent production of interferon-gamma and IL-12 cytokines and as suchinduces a cell mediated immune response.

In a further experiment, four (4) mice were administered with 500ug/mouse of PIKA (molecular weight range 66,000 to 660,000 Daltons) byperitoneal injection. A phosphate buffer solution was used as a negativecontrol test. Five hours after injection a blood sample was withdrawnand a serum prepared. The level of cytokines in the serum were assayedwith IL-12(p40) and interferon-gamma specific ELISA tests. The resultsof the experiment are presented in the table 11 below:

TABLE 11 Invivo Test for Cytokine Production IFN- gamma IL-12P40 Grouppg/ml pg/ml PBS 4 2 PIKA 410 40

The conclusion from the experiment above is that PIKA is effective instimulating a cell mediated immune response.

Example 13 Use of PIKA with Inactivated Purified Vero Cell RabiesAntigen

The objective of this experiment is to assess the effectiveness of PIKAin combination with an inactivated purified vero cell rabies vaccine(PVRV).

PIKA with a molecular weight range of 66,000 to 660,000 Daltons wascombined with PVRV to form a rabies vaccine. The NIH test was used toevaluate the potency of the resulting vaccine composition. Results arepresented in table 12 below:

TABLE 12 NIH Test Results for PIKA and Inactivated Purified Vero CellRabies Vaccine Vaccine Composition Composition Antigen Adjuvant Potency(IU/ml) PVRV 0.02 IU/ml n/a 0.46 PVRV plus PIKA 0.02 IU/ml PIKA 3.68

The conclusion drawn is that PIKA enhances the potency of theinactivated purified vero cell rabies vaccine.

Example 14 Antigen Dose

This experiment demonstrates the requirement to have a minimum amount ofhamster kidney cell inactivated purified rabies antigen (HKC-IPRA)present in the composition together with the PIKA adjuvant (molecularweight range from 66,000 to 660,000 Daltons) to trigger a substantiallyenhanced level of specific immune response.

Increased amounts of rabies antigen were added to a constant 0.1 mg ofPIKA adjuvant. The potency was measured using the NIH standard RabiesVaccine Potency Test. Following a predictable initial increase inpotency, a distinct and dramatic increase was observed before thepotency leveled off as expected with the addition of antigen (see table13).

TABLE 13 Vaccine Potency with Increasing Amounts of Hamster Kidney CellInactivated Purified Rabies Antigen HKC-IPRA plus Marginal 0.1 mg PIKAIncrease in HKC-IPRA (IU) (IU) Potency 0.25 0.42 — 0.51 1.43 3.88 1.012.73 2.60 1.40 6.07 8.56 2.07 19.78 20.46 2.91 21.38 1.90

The marginal increase in potency is the increase in the potency of theHKC-IPRA/PIKA vaccine observed for the addition of one IU of theHKC-IPRA present.

The conclusion drawn is that a minimum presence of antigen is necessarybefore a substantive immune response is induced. Furthermore excessiveantigen beyond that trigger point produces only a marginal incrementalreturn in potency.

Example 15 Antigen Adjuvant Ratio

This experiment demonstrates the optimum mix of hamster kidney cellinactivated purified rabies antigen (HKC-IPRA) and the PIKA adjuvant(molecular weight range 66,000 to 660,000).

Various quantities of antigen were mixed with various quantities ofadjuvant with PBS added to ensure a consistent overall volume. Thepotency of the resulting vaccines was determined using the NIH potencytest. The findings are presented in table 14.

Consideration of the combined test results indicates that the optimumvaccine combination is a ratio of PIKA to antigen in the range of atleast 3 to 1.

TABLE 14 Rabies Vaccine Potency at Various Antigen to Adjuvant RatiosHKC- Ratio IPRA PIKA (PIKA:HKC- Potency Samples (ml) (ml) PBS (ml) IPRA)ED50 (IU/ml) A 0.20 0.80 — 4.0 to 1 2.65 7.84 B 0.20 0.70 0.10 3.5 to 12.46 5.20 C 0.20 0.60 0.20 3.0 to 1 2.40 4.22 D 0.20 — 0.80   0 to 11.85 1.43 Standard na na 2.52 6.70

Example 16 Freeze-Dried Storage of PIKA and PIKA Combined with RabiesVaccine

This example demonstrates that PIKA is stable in a freeze-dried form.

Freeze-dried technology has been used for long term storage of rabiesvaccines for up to three years. The inventor sought to test whetherfreeze-dried storage of PIKA (of molecular weight range from 66,000 to660,000) and rabies vaccines containing PIKA would be beneficial. Thefollowing compositions were used for the freeze-dried storage test: i)unfrozen PIKA added to a reconstituted freeze-dried hamster kidney cellinactivated purified rabies antigen (HKC-IPRA), ii) reconstitutedfreeze-dried composition of PIKA plus HKC-IPRA, iii) a reconstitutedfreeze-dried commercial rabies vaccine (no added PIKA) and iv) anunfrozen commercial rabies vaccine. Table 15 shows that freeze-driedPIKA and PIKA-containing rabies vaccines were ideal for long termstorage of rabies vaccines.

TABLE 15 Effects of Freeze-dried Storage on the Potency of RabiesVaccines Relative Sample ED50 Potency IU/ml i) PIKA-diluted freeze-dried2.89 2.34 15.71 rabies vaccine ii) PBS-diluted freeze-dried 3.00 3.0020.23 PIKA-containing rabies vaccine iii) PBS-diluted freeze-dried 1.850.21 1.43 commercial rabies vaccine iv) Standard Rabies vaccine un- 2.521.00 6.70 frozen

While the present invention has been described with reference toparticular embodiments, it will be understood that the embodiments areillustrative and that the invention scope is not so limited. Alternativeembodiments of the present invention will become apparent to thosehaving ordinary skill in the art to which the present inventionpertains. Such alternate embodiments are considered to be encompassedwithin the spirit and scope of the present invention. Accordingly, thescope of the present invention is described by the appended claims andis supported by the foregoing description.

1. An immunogenic composition, comprising: a polynucleotide adjuvantcomposition comprising polynucleotide adjuvant composition moleculescomprising a polyriboinosinic polyribocytidylic acid (PIC), anantibiotic, and a positive ion, and an antigenic compound; wherein thepolynucleotide adjuvant composition molecules comprise molecules rangingfrom 9.0 Svedbergs to 12.0 Svedbergs or greater, and the composition issuitable for use in humans.
 2. The immunogenic composition of claim 1,wherein the polynucleotide adjuvant composition molecules have anaverage molecular size greater than 12 Svedbergs.
 3. The immunogeniccomposition of claim 1 or 2, wherein the antigenic compound is a humanantigen, a non-human animal antigen, a plant antigen, bacterial antigen,a fungal antigen, a viral antigen, a parasite antigen, or a cancerantigen.
 4. The immunogenic composition of claim 1 or 2, wherein theviral antigen is a rabies antigen.
 5. The immunogenic composition ofclaim 4, wherein the rabies antigen is an inactivated purified rabiesantigen.
 6. The immunogenic composition of claim 1 or 2, whereinpolynucleotide adjuvant composition is capable of eliciting an enhancedspecific humoral and/or cell mediated immune response.
 7. Theimmunogenic composition of claim 1 or 2, wherein the adjuvantcomposition and/or the immunogenic composition is in a solid form or aliquid form, wherein the liquid form is a solution or a suspension. 8.The immunogenic composition of claim 1 or 2, wherein at least one of theadjuvant composition or the immunogenic composition is freeze-dried. 9.A method for enhancing an immune response to an antigenic compound,comprising: administering to a subject a composition comprising anantigenic compound and the polynucleotide adjuvant composition of claim1 or
 2. 10. The method of claim 9, wherein said administering is byparenteral injection, intramuscular injection, intraperitonealinjection, intravenous injection, subcutaneous injection, inhalation,rectal delivery, vaginal delivery, nasal delivery, oral delivery,ophthalmic delivery, topical delivery, transdermal delivery orintradermal delivery.